Apologies if this is a recurring post and I haven't looked through past
posts properly.
I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is so
different about them to warrant the huge price difference. The choices are
(a) tubular heaters which fair enough are different, (b) fan heaters with
tubes (c) fan heaters without tubes. Has anyone any recommendations? I don't
really have roof space to hang a heater, it will need to go underneath the
benches, and I just want to keep the temp. through the winter at 8 to 10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.
Many thanks!
Paul

"Easynews" wrote in message
. ..

Apologies if this is a recurring post and I haven't looked through past
posts properly.
I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is so
different about them to warrant the huge price difference. The choices are
(a) tubular heaters which fair enough are different, (b) fan heaters with
tubes (c) fan heaters without tubes. Has anyone any recommendations? I
don't
really have roof space to hang a heater, it will need to go underneath the
benches, and I just want to keep the temp. through the winter at 8 to 10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.
Many thanks!
Paul

What are you intending to grow overwinter in an 18 x 10 greenhouse
that you need to heat it to 8 to 10 degrees ?

I'm asking that question because most people work the other
way around. They decide on what they're going to use the
greenhouse for over winter, on the basis of how much its going
to cost them in heating terms.

Have you actually worked that out?


michael adams

....

Easynews wrote:

I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is so
different about them to warrant the huge price difference. The choices are
(a) tubular heaters which fair enough are different, (b) fan heaters with
tubes (c) fan heaters without tubes. Has anyone any recommendations?

I prefer a fan heater since it stirs up the air and prevents cold spots
developing.

really have roof space to hang a heater, it will need to go underneath the
benches, and I just want to keep the temp. through the winter at 8 to 10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.

It had better be! Heating it all to 8-10C will cost you a fortune!!!

Far better to keep the closed end of a large greenhouse screened off
and fully heated, perhaps with a warm box inside for the really touchy
equatorial species. Then with luck the end near the door will stay
approximately frost free. My 3kW heater struggled to hold 5C minimum at
the warm end when the outside temperature was -12C or lower.

And you need to have a backup plan for mid-winter snowstorm power
failure.

Some experimentation with surplus seedlings to see how temperature
sensitive they really are is also worthwhile. Books generally err on
the side of caution.

Plants that are permanetly disfigured by cold like cacti & succulents
are a gamble. Small ones often are more sensitive, but wrecking a large
specimen plant is a bigger loss.

Regards,
Martin Brown

"michael adams" wrote in message
...

"Easynews" wrote in message
. ..

Apologies if this is a recurring post and I haven't looked through past
posts properly.
I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is so
different about them to warrant the huge price difference. The choices
are
(a) tubular heaters which fair enough are different, (b) fan heaters with
tubes (c) fan heaters without tubes. Has anyone any recommendations? I
don't
really have roof space to hang a heater, it will need to go underneath
the
benches, and I just want to keep the temp. through the winter at 8 to 10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.
Many thanks!
Paul

What are you intending to grow overwinter in an 18 x 10 greenhouse
that you need to heat it to 8 to 10 degrees ?

I'm asking that question because most people work the other
way around. They decide on what they're going to use the
greenhouse for over winter, on the basis of how much its going
to cost them in heating terms.

Have you actually worked that out?


michael adams

...

Hi Michael, yes, I know what I want to use the greenhouse for- as for the
cost of running, it is a hobby, hence does not have to be profitable or
particularly cost-effective- and there shouldn't be much difference in the
running cost of heaters with the same power rating (or correct me if I'm
wrong there?) The temperature I want is based on what is comfortable to work
in for long(ish) periods, rather than what is going to be grown, but also a
safe temperature for some insects that are more used to the Mediterranean.
There is also the option of just heating one part of the greenhouse, which
has a partition - but I need some help choosing a heater / type of heater. A
Frostshield 3kW fan heater with thermostat costs £50; a Bio Nevada 3kW fan
heater (with a thermostat & tube) costs £260. A Camplex 3kW fan heater with
thermostat costs £120. Apart from the shape I'm having trouble seeing the
benefits / disadvantages.

"Martin Brown" wrote in message
oups.com...

Easynews wrote:

I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is so
different about them to warrant the huge price difference. The choices are
(a) tubular heaters which fair enough are different, (b) fan heaters with
tubes (c) fan heaters without tubes. Has anyone any recommendations?

I prefer a fan heater since it stirs up the air and prevents cold spots
developing.

really have roof space to hang a heater, it will need to go underneath the
benches, and I just want to keep the temp. through the winter at 8 to 10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.

It had better be! Heating it all to 8-10C will cost you a fortune!!!

Far better to keep the closed end of a large greenhouse screened off
and fully heated, perhaps with a warm box inside for the really touchy
equatorial species. Then with luck the end near the door will stay
approximately frost free. My 3kW heater struggled to hold 5C minimum at
the warm end when the outside temperature was -12C or lower.

And you need to have a backup plan for mid-winter snowstorm power
failure.

Some experimentation with surplus seedlings to see how temperature
sensitive they really are is also worthwhile. Books generally err on
the side of caution.

Plants that are permanetly disfigured by cold like cacti & succulents
are a gamble. Small ones often are more sensitive, but wrecking a large
specimen plant is a bigger loss.

Regards,
Martin Brown

Thanks Martin. I have an 8 x 10 partition at the opposite end from the door.
We are on the coast, and temperature very rarely falls below -4. Power cuts
have been taken care of! Unfortunately I have around 300 baby cacti some of
which are very fussy about the cold- plus a few insects that I want to keep
happy. What do you think of the heaters with / without tubes attached?
Paul

On 5/9/06 10:26, in article , "michael adams"
wrote:


"Easynews" wrote in message
. ..

Apologies if this is a recurring post and I haven't looked through past
posts properly.
I am trying to decide which electric heater to buy for a fairly big
greenhouse
snip

What are you intending to grow overwinter in an 18 x 10 greenhouse
that you need to heat it to 8 to 10 degrees ?

I'm asking that question because most people work the other
way around. They decide on what they're going to use the
greenhouse for over winter, on the basis of how much its going
to cost them in heating terms.

Have you actually worked that out?

And if it's any help to the OP, we grow Agaves and the like but keep the
tunnels and greenhouses just frost-free. Nothing is forced so in the end,
the plants are stronger and don't die of shock when moved to a new home!
--
Sacha
www.hillhousenursery.co.uk
South Devon
http://www.discoverdartmoor.co.uk/

"Easynews" wrote in message
...

"michael adams" wrote in message
...

"Easynews" wrote in message
. ..

Apologies if this is a recurring post and I haven't looked through past
posts properly.
I am trying to decide which electric heater to buy for a fairly big
greenhouse (18' x 10') but a quick look at TwoWests catalogue shows 9
different heaters which vary from £41 to £259, and I can't see what is
so
different about them to warrant the huge price difference. The choices
are
(a) tubular heaters which fair enough are different, (b) fan heaters
with
tubes (c) fan heaters without tubes. Has anyone any recommendations? I
don't
really have roof space to hang a heater, it will need to go underneath
the
benches, and I just want to keep the temp. through the winter at 8 to
10
degrees C. Heaters would not be used in summer.
The greenhouse is well insulated.
Many thanks!
Paul

What are you intending to grow overwinter in an 18 x 10 greenhouse
that you need to heat it to 8 to 10 degrees ?

I'm asking that question because most people work the other
way around. They decide on what they're going to use the
greenhouse for over winter, on the basis of how much its going
to cost them in heating terms.

Have you actually worked that out?


michael adams

...

Hi Michael, yes, I know what I want to use the greenhouse for- as for the
cost of running, it is a hobby, hence does not have to be profitable or
particularly cost-effective- and there shouldn't be much difference in the
running cost of heaters with the same power rating (or correct me if I'm
wrong there?) The temperature I want is based on what is comfortable to
work
in for long(ish) periods, rather than what is going to be grown, but also
a
safe temperature for some insects that are more used to the Mediterranean.
There is also the option of just heating one part of the greenhouse, which
has a partition - but I need some help choosing a heater / type of heater.
A
Frostshield 3kW fan heater with thermostat costs £50; a Bio Nevada 3kW fan
heater (with a thermostat & tube) costs £260. A Camplex 3kW fan heater
with
thermostat costs £120. Apart from the shape I'm having trouble seeing the
benefits / disadvantages.


A one minute Google reveals that the the Bio Green Nevada incorporates
an air re-circulation system which is claimed to save up to 50% of energy
costs, whereas the Frostshield is a straightforward common-or-garden fan
heater.

Both can be found on the following page -

http://www.keengardener.co.uk/heaters.htm


michael adams

....

michael adams wrote:
"Easynews" wrote in message
...

Hi Michael, yes, I know what I want to use the greenhouse for- as for the
cost of running, it is a hobby, hence does not have to be profitable or
particularly cost-effective- and there shouldn't be much difference in the
running cost of heaters with the same power rating (or correct me if I'm
wrong there?) The temperature I want is based on what is comfortable to
work
in for long(ish) periods, rather than what is going to be grown,

NB You only really need that temperature in the daytime then... and it
would be a lot more cost effective to run in at 5C and wear an extra
layer of clothes. Or work in the greenhouse only on nice sunny winters
days when 10-15C is likely inside.

safe temperature for some insects that are more used to the Mediterranean.
There is also the option of just heating one part of the greenhouse, which
has a partition - but I need some help choosing a heater / type of heater.

Unless you really do need something special with a large slow fan or
huge power consumption I found the cheapest 3kW one operated with a
remote thermostat to be perfectly adequate fro a 10'x10' warm end of a
10'x20' greenhouse.

Frostshield 3kW fan heater with thermostat costs £50; a Bio Nevada 3kW fan
heater (with a thermostat & tube) costs £260. A Camplex 3kW fan heater
with
thermostat costs £120. Apart from the shape I'm having trouble seeing the
benefits / disadvantages.

A one minute Google reveals that the the Bio Green Nevada incorporates
an air re-circulation system which is claimed to save up to 50% of energy
costs, whereas the Frostshield is a straightforward common-or-garden fan
heater.

I would take all such energy saving claims with a huge pinch of salt.
The main losses from a greenhouse are leaks and drafts (or essential
ventilation for gas or kerosene burners) and conduction/convection
through the glass windows. Twinwall insulated polycarbonate gives a
worthwhile improvement in thermal insulation as does much cheaper
bubble wrap.

Regards,
Martin Brown

A one minute Google reveals that the the Bio Green Nevada incorporates
an air re-circulation system which is claimed to save up to 50% of energy
costs, whereas the Frostshield is a straightforward common-or-garden fan
heater.

Both can be found on the following page -

http://www.keengardener.co.uk/heaters.htm


michael adams

...
Thanks for the link. I've ordered Bio Green Phoenix.